Ultrasound System and Method for Segmenting Vessels

ABSTRACT

There are disclosed embodiments for an ultrasound system for performing segmentation of vessels. The ultrasound system comprises: an ultrasound data acquisition unit configured to transmit an ultrasound signal to a target object including vessels, receive an ultrasound echo signal reflected from the target object and form ultrasound data corresponding to the target object; a volume data forming unit configured to form volume data based on the ultrasound data; and a processor configured to form a 3-dimensional ultrasound image based on the volume data, set a plurality of slices on the 3-dimensional ultrasound image and perform segmentation of the vessels based on a degree of registration between the respective vessels on the adjacent slices.

The present application claims priority from Korean Patent ApplicationNo. 10-2009-0072559 filed on Aug. 7, 2009, the entire subject matter ofwhich is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to ultrasound systems, and moreparticularly to an ultrasound system and method for segmenting vessels.

BACKGROUND

An ultrasound system has been extensively used for acquiring internalinformation of a target object due to its non-invasive andnon-destructive nature. Since the ultrasound system may provide a highresolution image without any surgical treatment, it has proven to bevery helpful in the medical profession.

Generally, the ultrasound system may provide 3-dimensional ultrasoundimages including clinical information such as spatial information andanatomical information which 2-dimensional ultrasound images do notinclude. The ultrasound system may operate to transmit an ultrasoundsignal to a target object, receive the ultrasound signal reflected fromthe target object (i.e., ultrasound echo signal), and acquire ultrasounddata. The ultrasound system may form volume data by using the acquiredultrasound data and provide a 3-dimensional image through rendering ofthe formed volume data.

Also, the ultrasound system may operate to perform segmentation on the3-dimensional ultrasound image and extract an object of interest fromthe 3-dimensional ultrasound image. However, if a structure of vessel iscomplicated after performing segmentation, then it is difficult torecognize a specific vessel among many vessels as well as to locatevessel connection points (or junctions).

SUMMARY

There are disclosed embodiments of an ultrasound system and a methodadapted to set a plurality of slices on a 3-dimensional image andperform segmentation of vessel by using location difference betweenvessel edges on adjacent slices. In one embodiment, by way ofnon-limiting example, the ultrasound system comprises: an ultrasounddata acquisition unit configured to transmit an ultrasound signal to atarget object including vessels, receive an ultrasound echo signalreflected from the target object and form ultrasound data correspondingto the target object; a volume data forming unit configured to formvolume data based on the ultrasound data; and a processor configured toform a 3-dimensional ultrasound image based on the volume data, set aplurality of slices on the 3-dimensional ultrasound image and performsegmentation of the vessels based on a degree of registration betweenthe respective vessels on the adjacent slices.

In another embodiment, a method of performing segmentation of vesselscomprises: a) transmitting an ultrasound signal to a target objectincluding vessels and receiving an ultrasound echo signal reflected fromthe target object to thereby form ultrasound data corresponding to thetarget object; b) forming volume data based on the ultrasound data; c)forming a 3-dimensional ultrasound image based on the volume data; d)setting a plurality of slices on the 3-dimensional ultrasound image; ande) performing segmentation of the vessels based on a degree ofregistration between the respective vessels on the adjacent slices.

The Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key or essentialfeatures of the claimed subject matter, nor is it intended to be used indetermining the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an illustrative embodiment of anultrasound system.

FIG. 2 is a block diagram showing an illustrative embodiment of anultrasound data acquisition unit.

FIG. 3 is a block diagram showing an illustrative embodiment of aprocessor.

FIG. 4 is a schematic diagram showing an example of a plurality ofslices and vessel edges.

FIG. 5 is a schematic diagram showing an example of location differencebetween vessel edges on adjacent slices.

FIG. 6 is a schematic diagram showing an example of segmentation ofvessel.

DETAILED DESCRIPTION

A detailed description may be provided with reference to theaccompanying drawings.

FIG. 1 is a block diagram showing an illustrative embodiment of anultrasound system 100. The ultrasound system 100 comprises an ultrasounddata acquisition unit 110, a volume data forming unit 120, a processor130, a display unit 140 and a control unit 150.

The ultrasound data acquisition unit 110 may be operable to transmit anultrasound signal to a target object, receive the ultrasound signal(i.e., ultrasound echo signal) reflected from the target object, andacquire ultrasound data.

FIG. 2 is a block diagram showing an illustrative embodiment of theultrasound data acquisition unit 110. The ultrasound data acquisitionunit 110 may include a transmit signal forming unit 210, an ultrasoundprobe 220 including a plurality of transducer elements (not shown), abeam former 230 and an ultrasound data forming unit 240.

The transmit signal forming unit 210 may be operable to form a transmitsignal to be applied to each of the transducer elements of theultrasound probe 220. By way of a non-limiting example, the positionsand focusing points of the transducer elements may be considered informing the transmit signal. In one embodiment, the transmit signal mayinclude a transmit signal for acquiring a plurality of frames of thetarget object.

The ultrasound probe 220 may operate to convert the transmit signalprovided by the transmit signal forming unit 210 into an ultrasoundsignal and transmit it to the target object. The ultrasound probe 220may further operate to receive the ultrasound echo signal reflected fromthe target object and form a receive signal.

The beam former 230 may be configured to form a digital signal throughanalog-to-digital conversion of the receive signal provided by theultrasound probe 220. The beam former 230 may operate to performreceive-focusing upon the digital signal in consideration of thepositions and focusing points of the transducer elements, and form areceive-focused signal thereby.

The ultrasound data forming unit 240 may be configured to formultrasound data of the target object using the receive-focused signalprovided by the beam former 230. In one embodiment, the ultrasound datamay comprise RF (radio frequency) data and IQ (in-phase/quardrature)data.

Referring back to FIG. 1, the volume data forming unit 120 may operateto form volume data by using the ultrasound data provided by theultrasound acquisition unit 110. The volume data may comprise aplurality of frames and a plurality of voxels having brightness values.

The processor 130 may operate to form a 3-dimensional ultrasound imageincluding vessels in the target object by using the volume data providedby the volume data forming unit 120, and perform segmentation of thevessels by using the 3-dimensional ultrasound image.

FIG. 3 is a block diagram showing an illustrative embodiment of theprocessor 130. The processor 130 comprises an image forming unit 310, anedge detection unit 320, a slice setting unit 330 and a segmentationunit 340.

The image forming unit 310 may operate to form the 3-dimensionalultrasound image through rendering of the volume data provided by thevolume data forming unit 120. In one embodiment, the rendering maycomprise ray-casting rendering, surface rendering, etc.

The edge detection unit 320 may operate to detect vessel edges throughperforming edge detection on the 3-dimensional ultrasound image providedby the image forming unit 310. In one embodiment, the vessel edges maybe detected by using an edge mask such as a Sobel mask, a Prewitt mask,a Robert mask, a Canny mask, etc. Also, the vessel edges may be detectedfrom the difference of eigen values by using a structure tensor.

The slice setting unit 330 may operate to set a plurality of slices(S₀-S_(n)) on the 3-dimensional ultrasound image in which the vesseledges were detected, as illustrated in FIG. 4. In one embodiment, theplurality of slices may comprise slices corresponding to the pluralityof frames.

The segmentation unit 340 may be configured to perform segmentation ofthe vessels based on a degree of registration between the respectivevessels on the adjacent slices. In one embodiment, the segmentation unit340 may operate to compare the location of vessels on adjacent slices byusing the vessel edges and perform segmentation of the vessels.Following is illustrative operation of the segmentation unit 340 withreference to FIG. 4.

The segmentation unit 340 may operate to analyze a first slice (S₁) anddetect vessel edges (VE₁₁, VE₁₂) on the first slice (S₁).

The segmentation unit 340 may operate to analyze a second slice (S₂) anddetect vessel edges (VE₂₁, VE₂₂) on the second slice (S₂). Thesegmentation unit 340 may operate to detect location difference betweenthe vessel edges on the adjacent slices (i.e., the first slice (S₁) andthe second slice (S₂)), as illustrated in FIG. 5. Specifically, thesegmentation unit 340 may operate to detect the location differencebetween the vessel edge (VE₁₁) of the first slice (S₁) and the vesseledge (VE₂₁) of the second slice (S₂) as well as the location differencebetween the vessel edge (VE₁₁) of the first slice (S₁) and the vesseledge (VE₂₂) of the second slice (S₂). Further, the segmentation unit 340may operate to detect the location difference between the vessel edge(VE₁₂) of the first slice (S₁) and the vessel edge (VE₂₁) of the secondslice (S₂) as well as the location difference between the vessel edge(VE₁₂) of the first slice (S₁) and the vessel edge (VE₂₂) of the secondslice (S₂). In case that the location difference between the vessel edge(VE₁₁) of the first slice (S₁) and the vessel edge (VE₂₁) of the secondslice (S₂) and the location difference between the vessel edge (VE₁₂) ofthe first slice (S₁) and the vessel edge (VE₂₂) of the second slice (S₂)are equal to or less than a predetermined threshold, and the locationdifference between the vessel edge (VE₁₁) of the first slice (S₁) andthe vessel edge (VE₂₂) of the second slice (S₂) and the locationdifference between the vessel edge (VE₁₂) of the first slice (S₁) andthe vessel edge (VE₂₁) of the second slice (S₂) are more than thepredetermined threshold, the segmentation unit 134 may connect thevessel edge (VE₂₁) of the second slice (S₂) with the vessel edge (VE₁₁)of the first slice (S₁), and connect the vessel edge (VE₂₂) of thesecond slice (S₂) with the vessel edge (VE₁₂) of the first slice (S₁).The segmentation unit 340 may perform the same operation with respect toa third slice (S₃) and a fourth slice (S₄), as described above.

The segmentation unit 340 may operate to analyze a fifth slice (S₅) anddetect a vessel edge (VE₅) on the fifth slice (S₅). The segmentationunit 134 may operate to detect the location difference between thevessel edges on the adjacent slices (i.e., the fourth slice (S₄) and thefifth slice (S₅)). In case that the location difference between thevessel edge (VE₄₁) of the fourth slice (S₄) and the vessel edge (VE₅) ofthe fifth slice (S₅) and the location difference between the vessel edge(VE₄₂) of the fourth slice (S₄) and the vessel edge (VE₅) of the fifthslice (S₅) are equal to or less than the predetermined threshold, thesegmentation unit 340 may connect the vessel edge (VE₅) of the fifthslice (S₅) with the vessel edges (VE₄₁, VE₄₁) of the fourth slice (S₄).

The segmentation unit 340 may operate to analyze a sixth slice (S₆) anddetect a vessel edge (VE₆) on the sixth slice (S₆). The segmentationunit 340 may operate to detect the location difference between thevessel edges on the adjacent slices (i.e., the fifth slice (S₅) and thesixth slice (S₆)). In case that the location difference between thevessel edge (VE₅) of the fifth slice (S₅) and the vessel edge (VE₆) ofthe sixth slice (S₆) are equal to or less than the predeterminedthreshold, the segmentation unit 340 may connect the vessel edge (VE₆)of the sixth slice (S₆) with the vessel edge (VE₅) of the fifth slice(S₅).

The segmentation unit 340 may perform the same operation with respect toa seventh to an nth slice (S₇-S_(n)) as described above in order toperform segmentation of the vessels, as illustrated in FIG. 6.

Referring back to FIG. 1, the display unit 140 may operate to displaythe 3-dimensional ultrasound image formed by the processor. The displayunit 140 may further operate to display the 3-dimensional ultrasoundimage on which the processor 130 performed segmentation of the vessels.In one embodiment, the display unit 140 may include a liquid crystaldisplay (LCD), a cathode ray tube (CRT) or any other device capable ofdisplaying an image.

The control unit 150 may operate to control acquisition of theultrasound data, and formation of the volume data and the 3-dimensionalultrasound image. The control unit 150 may further operate to controlimage processing of the 3-dimensional ultrasound image (i.e.,segmentation of the vessels).

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, numerous variations andmodifications are possible in the component parts and/or arrangementswithin the scope of the disclosure, the drawings and the appendedclaims. In addition to variations and modifications in the componentparts and/or arrangements, alternative uses will also be apparent tothose skilled in the art.

1. An ultrasound system, comprising: an ultrasound data acquisition unitconfigured to transmit an ultrasound signal to a target object includingvessels, receive an ultrasound echo signal reflected from the targetobject and form ultrasound data corresponding to the target object; avolume data forming unit configured to form volume data based on theultrasound data; and a processor configured to form a 3-dimensionalultrasound image based on the volume data, set a plurality of slices onthe 3-dimensional ultrasound image and perform segmentation of thevessels based on a degree of registration between the respective vesselson the adjacent slices.
 2. The ultrasound system of claim 1, wherein theprocessor is further configured to compare the degree of registrationwith a predetermined threshold.
 3. The ultrasound system of claim 1,wherein the processor further comprises: an edge detection unitconfigured to detect edges of the vessels on the plurality of slices;and a segmentation unit configured to calculate location differencesbetween the edges of the vessels on each adjacent pair of the slices andperform segmentation of the vessels based on the location differences.4. A method of performing segmentation of vessels, comprising: a)transmitting an ultrasound signal to a target object including vesselsand receiving an ultrasound echo signal reflected from the target objectto thereby form ultrasound data corresponding to the target object; b)forming volume data based on the ultrasound data; c) forming a3-dimensional ultrasound image based on the volume data; d) setting aplurality of slices on the 3-dimensional ultrasound image; and e)performing segmentation of the vessels based on a degree of registrationbetween the respective vessels on the adjacent slices.
 5. The method ofclaim 4, wherein the performing segmentation of the vessels comprisescomparing the degree of registration with a predetermined threshold. 6.The method of claim 4, wherein the performing segmentation of thevessels comprises: detecting edges of the vessels on the plurality ofslices; calculating location differences between the edges of thevessels on each adjacent pair of the slices; and performing segmentationof the vessels based on the location differences.
 7. The method of claim6, wherein the performing segmentation of the vessels comprisescomparing the location differences with a predetermined threshold.